Category: radio

Since I got my Arrow Antenna, I've been trying to contact all 50 states by satellite (aka Worked All States). I know a few states are going to be tough (if they're even possible). I know Alaska and Hawaii will probably have to be a scheduled contact. Since the pass that will allow us to contact each other will be very low on the horizon. I have been getting about 2 passes a day from the satellite AO-27, one usually to the east then the second passing more to the west. I've been steadily adding states as I hear them. I'm also making contacts via Echo (AO-51) which is very busy on it's nightly passes.

If it weren't for the listing on Heavens Above, I'd prob be lost as to when to listen for a satellite. For those stations that have sent me a QSL card, I will send out a batch as soon as my new ones arrive. The map above is a listing of those states which I've contacted (yellow) and those that I've received a QSL card from (green).

This past Thursday afternoon I received my new Arrow Antenna. It's a dual-band (2m/70cm) handheld yagi antenna made from aluminum arrow shafts for making contacts with amateur radio satellites. What? You didn't know there were ham radio satellites? Yep, and there's more than one.

Using Heavens-Above, I can find when each satellite will be making a pass over my location as well as the angle and direction of the approach and apex. About an hour after I got the antenna, AO-27 was making one of its daily passes over me. I made sure everything was in order, set my radio to the right frequencies and walked to the field across from my house. Right off the bat I heard guys in New England talking with guys in Florida. Most everyone on the air was using a handheld with relatively low power (under 5W, which normally isn't enough to even get you across town). After just a few minutes I heard my chance to throw out my call. Right away I had two stations come back to me. First time to ever hear the satellite and I was making a contact on one. Unfortunately I didn't have a free hand to write down his callsign and I forgot it! Oops!

How does it work? Essentially the little satellite takes my signal and rebroadcasts it like a ground-based repeater does, only it's up - way up. Because it's up so high, it can rebroadcast my signal to most of North America. To hear me all the other station has to do is listen on the "downlink" frequency.
Really it doesn't take any special antenna to allow this, it's just this antenna is very efficient and easy to aim at just the right spot. Sometime in the future I'd like to try to make an altazimuth mount to automatically steer the antenna for me, but that's way down the road. For now I'm just looking forward to the next satellite pass!

I've been messing with some scripts lately that fill a couple of online niches for ham radio. Most of the visitors to Neodux might not find them very useful, but I'm linking it here for posterity and to explain to any visitor looking for ham radio information what they can find.
http://n5dux.com/ham/
At the moment I have 3 tools up. First is a script that fetches the number of ham radio licenes issued in a given month and saves the data in an XML file. I then parse the XML files to create a table or graph. (Just nice to know for anyone curious.)

Next is a dynamic image that will create a map for any ham trying for a "Worked All States" award. It colors in states as you check them off your list. (This was one I made a couple of years ago, but I thought it should be included.)

Lastly, I have a notification script. When you take your FCC test, you have to wait for the FCC to post your information in their database. Rather than hunting it down yourself and checking daily for any news, you can put your name on the list to be notified and the script will shoot you an email when your name is posted.

I hope any ham-visitors find them interesting and useful. That is all.

update: I just added a second color to the WAS map. States listed with the verified tag, will turn green. This is to denote the states from which a QSL card has been received.

Well, it's taken me a while to make a post about this one. It was a goal of mine after I completed the simple foxhole radio and one I set out to complete over the Christmas break. I decided since the crystal set was the simplest radio to build, what's the next step? The one-tube regenerative circuit was the answer.

Lately I've been reading quite a bit about radio history and have read about the huge leaps in receiver technology with the advent of the "audion" or vacuum tube. A lot of initial growth in radio reception is thanks to this circuit designed by Edwin Armstrong while still a junior in college in the early 1900s.

I scoured the net looking for parts (chiefly the 3S4 tubes) and kept coming back to Borden Radio Company. Rather than drop alot of money on shipping from various sources, I purchased a kit from Borden. It also happens that he doesn't live too terribly far from my parent's so I was able to meet up with the owner/operator, Lance Borden, over the Christmas holiday.

I pieced the kit together in two evenings. The first evening was spent winding the coils and mounting the hardware. The next night was spent meticulously wiring the components as outlined in the directions. (Maybe color coding the wires would have made the instructions a little clearer, but I can't complain.) The radio worked right from the get-go. It's tuned for broadcast AM reception and works like a charm. As you can see in the picture it requires quite a few batteries to power the tube, but it is 100 times louder than the crystal set and much more sensitive. I've heard stations all over the nation on this little set. This evening alone I was able to quickly tune into WWL 870 from New Orleans as well as KOA 850 out of Denver, Colorado.

The controls are finicky and not really what the casual listener would want, but the sensitivity and simplicity makes it worth the effort. Aiding reception is the clear audio produced by the old high-impedence Allied Radio headset that I purchased with the kit. The owner of Borden Radio assured me I wouldn't be disappointed with the headset as it works so much better than the old ear piece I had been using - boy was he right!

So, if you're following my steps through the old style radio setups, this is a step you definitely don't want to skip.

Another shot of the radio is here. (I tried to get a shot of the dim glow of the tubes, but the camera just wasn't able to capture the almost imperceptible light from within the tube.)

Next up: Super-regen? Super-het? FM ? (the passive FM is almost too tempting)

After the success of my last post about my simple razor-blade radio (link here), I began work on making a slinky dipole. I tried to use 2 Slinky Jr. toys which I bought at Walmart for $.88 each. It didn't work as well as I had hoped. After quite a while of the coils sitting on my desk and playing with them, it dawned on me that I could easily use the small Slinkys as the tuning coil for a simple radio. I started to do the math to find the inductance of the coils. I measured 1.5" in diameter, which gave me 4.7" in circumference. I started to count the coils to calculate the open-air coil formula that I had used before. I stopped and thought, why bother? Just try it out!

I stretched the slinky to the length of the board I used on the old razor-blade radio and tacked it down. I made the proper connections, using a diode first. (Ground went to the 3rd prong on a power outlet, the antenna wire and clip was hooked to my 20m ham radio antenna, on my roof) I started with the diode because it is far more efficient than the razor blade, which equates to louder audio in the earpiece.

Right off the bat I was able to hear shortwave broadcast stations! Wilder still was my ability to receive the signal without having the antenna clip attached! I tried various points along the coil, finding I was able to hear certain stations better at different points on the coil. As before, I was able to hear local AM broadcast stations just fine, and various strong shortwave stations with a "shorter tap".
After listening with the diode for a few minutes, once again amazed at the simplicity of the setup, I switched to the razor blade setup I had used in the past and was just able to pull out the same local broadcast signal from before. The key to using the razor blade/saftey pin is using a pencil lead wrapped soldered to the pin. Then ever-so-lightly "fishing" for the sweet spot on the razor that allows the signal to pass. It's also important to note you'll need to be in a fairly quiet environment to hear the signal, but if you listen - it's there.

So now you have no excuse but to find a crystal set earpiece, the coil has been made for you and it'll cost you under a dollar to buy. Alligator clips help, but as you can see, are not 100% necessary. Also note at the top of the picture is the old coil from my last setup.